Simultaneous determination of four isoflavonoids in radix astragali by HPLC

Aim To establish a RP-HPLC method for simultaneous determination of calycosin 7-O-β-D-glucoside(Ⅰ),formononetin 7-O-β-D-glucoside(Ⅱ),calycosin(Ⅲ)and formononetin(Ⅳ)in radix astragali.Methods These four isoflavonoids were successfully analyzed on a C18 reversed-phase chromatographic column(4.6 mm×250 mm,5 μm) by gradient elution using water and acetonitrile as the mobile phase at room temperature.Detection wavelength was set at 254 nm.Results The method showed good linearity in the ranges of(Ⅰ) 5.16~660 mg·L-1(r=0.999 8),(Ⅱ) 1.18~150 mg·L-1(r=0.999 9),(Ⅲ) 2.89~370 mg·L-1(r=0.999 9) and(Ⅳ) 4.22~540 mg·L-1(r=0.999 8) for the four isoflavonoids respectively;and the mean recovery(n=3)of the four invested compounds were(Ⅰ)101.4%(RSD=2.97%),(Ⅱ)95.2%(RSD=2.17%),(Ⅲ)105.4%(RSD=0.93%) and(Ⅳ)96.9%(RSD=3.13%).Conclusion The developed new method is simple,precise,accurate,and reliable for quality evaluation of radix astragali.